AN1506 Datasheet, PDF (12/14 Pages) STMicroelectronics – A MOTOR DRIVES SYSTEM FOR WHEELCHAIR APPLICATIONS

AN1506 - APPLICATION NOTE
Figure 12. Total power losses at two switching frequencies (1kHz and 24.5kHz), and conduction
losses in a power MOSFET of the inverter leg
6. CONCLUSION.
A full characterization of the device has been presented. First of all the MOSFET has been tested in
order to evaluate the static and dynamic performances by traditional procedures. Then the device
behavior has been investigated in a conventional chopper circuit, and several switching cycles have
been performed in order to define, at constant clamp voltage, the trend of the energy losses as function
of the drain current. A full characterization on a specific battery-powered converter has been presented
and discussed. In particular, an analysis of the power losses has been previously carried out aiming to
calculate and separate the switching and conduction contributions in such an application. Finally an
experimental validation by a steady state thermal behavior has been performed to apply the analytical
relations that have been determined. The results are interesting thus encouraging the use of the internal
diode as antiparallel diode. In conclusion, the power MOSFETs presented has been demonstrated to be
very suitable for inverter bridges in the field of commercial and industrial applications working at low
voltage.
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